Biodegradation of blends

Two different types of biodegradable pofyester composites, PLLA fibre-reinforced PCL and PCL/PLLA blend films, were prepared with a PCL/PLLA ratio of 88/12 (w/w) and their 

The degradation of atactic poly(R,S)-3-hydroxybutyrate (a synthetic amorphous analogue of natural PHB), binary blends with natural PHB and pofy(L-lactic acid) (PLLA), respectively, has been investigated in soil [129]. In such a natural environment, a-PHB blend component was found to biodegrade. The degradation of a-PHB-containing blends proeeeded faster than that of respective plain n-PHB and PLLA. 

The biodegradabihty of native and compatibilized poly(e-caprolactone) (PCL)-granular starch blends in composting and culture conditions was studied. The inherent biodegradability of the host polyester has been shown to increase with compatibilization within the PCL-starch compositions [131]. It was observed that the weight loss during composting increased with the 

Biodegradation of blends of pofy(e-caprolaetone) (PCL) with poly(vit5 l butyral) (PVB) blends was studied in the soil and by baeterial strains of Bacillus subtilis and Escherichia coli isolated from the soil [135]. Weight loss was observed in all the blends. PCL-rich blends showed more degradation, which was faster in the natural environment than in the laboratory. Blends in the Bacillus subtilis strain showed more degradation as eompared to the E. coli strain. 

Poly(L-lactic acid) (PLLA) and poly(e-caprolactone) (PCL), and their films blended with or without 50wt% pofy(etl5rlerte glycol) (PEG), were prepared by solution easting [137]. Porous films were obtained by water extraetion of PEG from solution-cast phase-separated PLLA-blend-PCL-blend-PEG films. Polymer blending as well as pore formation enhanced the enzymatic degradatiort of biodegradable polyester blends. 

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Tilstra, L., and Johnsonbaugh, D., 1993, The biodegradation of blends of polycaprolactone and polyethylote exposed to a defined consortium of fungi. J. Environ. Polym. Degrad. 1 257-267. 

In the present contribution an investigation on the biodegradation of blends and graft copolymers of PHB of both natural and synthetic origin and PVA/PVAc blends is reported. The evaluation of the effects of each component in blends and copolymers on both the overall extent of biodegradation and the biodegradation of counterparts, was investigated in aqueous media and in soil by means of respirometric tests. 

After a lack of interest in these blends for some 20 years, there were some new developments in this field. Thus, protein silver was incorporated in NR to produce antimicrobial latex compositions." Proteins were also used to produce conductive rubber." Collagen protein fibres were incorporated in NR to produce studless tyres exhibiting good properties at low temperatures." Proteins were also cited as potential biofillers for accelerating the biodegradability of blends mainly composed of polyolefins and rubbers." ... 

Gilmore, D. F., Lotti, N. and Lenz, R. W. et al. (1992) Biodegradability of blends of poly(hydroxybutyrate-co-hydroxyvalerate) with ester-substituted celluloses, in Biodegradable Polymers and Plastics (eds M. Vert et al.). Royal Society of Chemistry, Cambridge, pp. 251-4. 

BIODEGRADATION OF BLENDS CONTAINING POLY (3-HYDROXYBUTYRATE-CO-VALERATE)... 

D.F. Gilmore, N. Lotti, R.W. Lenz, R.C. Fuller and M. Scandola, "Biodegradability of blends of poly(hydroxybutyrate-co- hydroxyvalerate) with ester-substituted celluloses", in "Biodegradable Polymers and Plastics", M. Vert, J. Feijen, A. Albertsson, G. Scott and E. Chiellini eds.. Royal Society of Chemistry, London, 251-254,1992. 

Gajria A M, Dave V, Gross R A, McCarthy S P (1996), Miscibility and biodegradability of blends of poly (lactic acid) and poly (vinyl acetate) . Polymer, 37, 437-444. 

Skaija GA and Woodhouse KA. In vitro degradation and erosion of degradable, segmented pol3mreth-anes containing amino acidbased chain extender. J Biomater Sci Polym Ed, 2001, 12, 851-873. Fromstein JD and Woodhouse KA. Elastomeric biodegradable polyurethane blends for soft hssue application. J Biomater Sci Polym Ed, 2002, 13, 391 06. 

Despite the fact that physico-chemical and chemical degradations were not possible, the isolation of persistent metabolites of the CnF2n+i-(CH2-CH2-0)m-H compound generated by (3 and w oxidations of the terminal PEG unit of the non-ionic blend was reported, but environmental data about this type of compound are still quite rare [49]. TSI(+) ionisation results of the industrial blend Fluowet OTN have been reported in the literature [7,51]. Actual data of non-ionic fluorinated surfactants were applied using ESI- and APCI-FIA-MS(+) and -MS-MS(+), which reported the biodegradation of the non-ionic partly fluorinated alkyl ethoxylate compounds C F2 fi-(CH2-CH2-0)x-H in a lab-scale wastewater treatment process. 

The second section deals with the degradability of commodity plastics and specialty potymers. Emphasis is on the biodegradation of polyethylene, its blends with starch, and constraints in the decay of such composites. Additionally, the biodegradability of different functional groups (polyethers, carbotylic adds, esters, and dioxanones) is mcamined with respect to composition and miaostructure. 

Other uses of blends include controlled rate of fertilizer release(77) based on ethylene/vinyl acetate/carbon monoxide polymers which is U.V. sensitive, polyolefin blends with any biodegradable polymers,(78) and polyolefins blended with metals and autoxidizable substrates. (79) Doane and co-workers(80) at the U.S.D.A. have used grafted starches in many applications, including soil stabilization. 

The susceptibility of CPAEs to hydrolysis by R. delemar lipase decreased with the shortening of the polyamide blocks and with increasing polyamide content (Figure 10). The simple blends of nylon and PCL at 270 °C for 10 min retained high biodegradability of PCL. 

When looking at the life cycle of biodegradable plastics, two aspects are of particular importance the end-of-life options and the use of renewable resources in the material production (the major part of the currently available biodegradable plastic products are made of blends of fossil-based polymers and polymers derived from biomass). 

The proprietary chemical blends or cleaners effectively accelerate the biodegradation of most organic pollutants. 

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